There are two forms of the molecule, NAD+, and the other NADH.
Nad precursors include nicotinamide, nicotinamide riboside, nicotinamide mononucleotide, but what exactly is the difference between NAD+ and NADH?
To put it simply, one form of the molecule is holding onto an electron and the other is not. When NADH donates an electron, it becomes NAD+, and when NAD+ takes an electron from another molecule it becomes NADH.
The fact of the matter is that without either form of this molecule, we wouldn’t be able to lead fruitful lives, let alone survive.